System and method for metering fuel in a high pressure pump system

Abstract

A system and method for metering fuel is provided which includes a fuel supply line and a metering valve in fluid connection with the fuel supply line to control a flow of fuel through the fuel supply line. The valve is movable into a closed position to block a primary flow of fuel and create a leakage fuel flow in the fuel supply line downstream of the metering valve. The system also includes a venturi apparatus fluidly coupled to the fuel supply line upstream of the metering valve. The venturi apparatus is further coupled to the fuel supply line downstream of the metering valve to direct the leakage fuel flow out of the fuel supply line.

1. A system for metering fuel to at least one high pressure fuel pump, comprising:
 a fuel supply line in fluid connection with said at least one high pressure fuel pump; 
 a metering valve in fluid connection with said fuel supply line to control a flow of fuel through said fuel supply line, said valve movable into a closed position to block a primary flow of fuel and create a leakage fuel flow in said fuel supply line downstream of said metering valve; and 
 a venturi apparatus fluidly coupled to said fuel supply line upstream of said metering valve, said venturi apparatus further coupled to said fuel supply line downstream of said metering valve to direct said leakage fuel flow away from said at least one high pressure fuel pump. 
 
   
   
     2. The system of  claim 1 , wherein said at least one high pressure fuel pump comprises a plurality of high pressure fuel pumps. 
   
   
     3. The system of  claim 1 , wherein the venturi apparatus directs gas out of said fuel supply line. 
   
   
     4. The system of  claim 1 , wherein the venture apparatus is configured to produce a low pressure region downstream to the metering valve when said material valve is closed. 
   
   
     5. The system of  claim 4 , wherein the low pressure region is maintained between approximately 5-10 psi. 
   
   
     6. The system of  claim 1 , further comprising:
 an outlet of said venturi apparatus; and 
 a fuel drain line fluidly coupled to the outlet and the at least one high pressure pump, wherein the venturi apparatus directs fuel in the fuel drain line away from said at least one high pressure pump. 
 
   
   
     7. A high pressure fuel injection system for pressurizing a common rail fuel apparatus to a predetermined pressure range comprising:
 at least one high pressure fuel pump coupled to said common rail fuel apparatus; 
 a fuel supply line in fluid connection with said at least one high pressure fuel pump; 
 a metering valve in fluid connection with said fuel supply line to control a flow of fuel through said fuel supply line, said valve movable into a closed position to block a primary flow of fuel and create a leakage fuel flow in said fuel supply line downstream of said metering valve; and 
 a venturi apparatus fluidly coupled to said fuel supply line upstream of said metering valve, said venturi apparatus further coupled to said fuel supply line downstream of said metering valve to direct said leakage fuel flow away from said at least one high pressure fuel pump. 
 
   
   
     8. The system of  claim 7 , comprising:
 an outlet of said venturi apparatus; and 
 a fuel drain line fluidly coupled to the outlet and the at least one high pressure pump, wherein the venturi apparatus directs fuel in the fuel drain line away from said at least one high pressure pump. 
 
   
   
     9. A system for metering fuel to a high pressure fuel pump comprising:
 means for supplying fuel to a high pressure fuel pump; 
 means for metering the quantity of fuel supplied to the high pressure fuel pump at a point upstream to said high pressure fuel pump; and 
 venturi apparatus fluidly coupled to the means for supplying fuel upstream of the metering point, and fluidly coupled to the means for supplying fuel downstream of the metering point and upstream of said high pressure fuel pump, for preventing fuel from being pressurized by the high pressure fuel pump at a point downstream to the metering point and upstream to said high pressure fuel pump. 
 
   
   
     10. The system of  claim 9 , wherein the metering means comprises a hydro mechanical actuator. 
   
   
     11. The system of  claim 10 , wherein the hydro mechanical actuator includes an inlet metering valve. 
   
   
     12. A method of metering fuel to a high pressure fuel pump comprising:
 supply fuel to a high pressure fuel pump; 
 metering the quantity of fuel supplied to the high pressure fuel pump at a point upstream of said high pressure fuel pump; 
 preventing fuel from being pressurized by the high pressure fuel pump at a point downstream of the metering point the upstream of said high pressure fuel pump by using a venturi apparatus fluidly coupled to the fuel supply upstream of the metering point, and fluidly coupled to the fuel supply downstream of the metering point and upstream of said high pressure fuel pump, to form a low pressure zone in the fuel supply downstream of the metering point and upstream of said high pressure fuel pump. 
 
   
   
     13. The method of  claim 12 , further comprising:
 maintaining the low pressure zone between approximately 5-10 psi. 
 
   
   
     14. The method of  claim 12 , further comprising:
 removing gas from the fuel supply at a point upstream of the metering point. 
 
   
   
     15. A method of pressurizing an accumulator to a predetermined pressure range, comprising:
 suppling fuel to at least one high pressure fuel pump fluidly coupled to said accumulator; 
 metering the quantity of fuel supplied to the at least one high pressure fuel pump at a point upstream of said at least one high pressure fuel pump; 
 preventing fuel from being pressurized by said at least one high pressure fuel pump at a point downstream of the metering point and upstream of said at least one high pressure fuel pump by using a venturi apparatus fluidly coupled to the fuel supply upstream of the metering point, and fluidly coupled to the fuel supply downstream of the metering point and upstream of said high pressure fuel pump to form a low pressure zone in the fuel supply downstream of the metering point and upstream of said at least one high pressure fuel pump to regulate a pressure of the accumulator within a predetermined range. 
 
   
   
     16. The method of  claim 15 , further comprising:
 preventing pumping by the at least one high pressure fuel pump to regulate pressure of the accumulator.